Stabilized halogenated compositions and electrical devices



April 26, 1949. F. M. CLARK STABILIZED menu-an courosrnons AND mmcmxcnn nsvrcss Filed Nov. 10, 1945 CU/(Ml/M' M1065 MATEO HYWCAHBOI/ AND 4 ASSOC/4750 N57 3 117080011780 Fig. 2.

Fig.3. 50 k M 0 J6 Q 5 g; .u

'5 20 in la t go a .2 .4 .6 .a m u Pm cnvr m! rrrfinnwvn TIMPERAIVR! cnvz' Inventor: Frank MOlar'k,

His Attorney.

devices as dielectric.

Patented Apr. 26, 1949 UNITED STATES PATENT OFFICE 2.488.544 STABILIZED HAIHGENA'IID OOMPOSITIONS AND EIEG'I'BIOAL DEVICES Frontal. (llarlarlttsdeld. Haas, asaianorto Geno rai llleeirle compa y. a eorporadon at New Application November 10, 1915, Serial No. 621.834 10 Claims. 115-41) The present application is a continuation-inpart oi my priorapplication Serial lilo. 498,834. filed August 16, 1843. now abandoned. inventlon thereoi comprises compos tions or haloserrated hydrocarbons, and in particular. liquid chlorinated hydrocarbons. In accordance with my invention such compositions are associated with a minor amount. which may be less than one per cent. or cream-metallic compound, whereby the deleterious effect c! halogen decomposition product is inhibited Halogenated aryl hydrocarbons are relatively stable compounds. Halogenated alkyi compounds are less stable. beina dissociated but slightly even on standing. Decomposition or a halogenated aryl compound. however. may occur when such compound is brought into contact with an electric are. Some decomposition may even occur when such compound is subjected for ions perio s to voitaae stress (as in capacitors). especially at elevated temperatures.

Liquid. halogenated compounds oi benzene. diphenyl. and the like, are used in various electric insulating or cooling agents. The presence of product, contact with a halogenated compound. may damage such apparatus. For example. paper insulation in electric transformers is seriously depreciated by the preaence'oi' hydroflen chloride, especially when some moisture is present. oils or krait paper after even one day 0! exposure at 75'' C. to a liquid chlorinated hydrocarbon containing hydrogen chloride will lose 70 to 80 per cent or its tensile strength.

I have discovered that products can be rendered substantially innocuous if, in accordance with my present invention, a halogenated composition. which is in contact with insulating or other material to be protected. is associated with orgasm-metallic compound. Such compounds. which have a molecular carbonto-metal linkage, are described in Orsonie Chemistry by Gilinan. vol. I. poses ill and 492. This book was published in 1943 by John Wiley I: Sons. New York.

An organo-rnetailic compound, {or example. may have the formula m:- In this formula M represents a metal chosen from the group consisting of tin. lead, and mercury: it represents a plurality of aliphatic, alicyciic. or aromatic groups; and :1: represents an integer corresponding to the valency or the metal in the compound and numerically is within the limits 0! 2 to l.

halogen decoml ositlon lo. and

MRI may include compounds in which R represents only aliphatic. aromatic or alicyclic groups. It also includes compounds in which It represents combinations of the aliphatic. aromatalicyclic groups and includes compounds in which such groups contain substituents. such as chlorine or other halogen or hydroxyl or amine radicals. For example the iormula Mlle may include a metal combined directly with an aliphatic group or groups and also one or more aromatic or alicyclic srcups. An example of an oreanometallic compound containing such a multiplicity of unlike groups is dibutyl diphenyl tin.

other examples or an creme-metallic compound capable 0! use as an inhibitor in accordance with my invention are compounds havina the formula MR8 in which It represents organic groups or combinations thereof as previously stated and Y represents lnorzanic substituent radical. such as halogen or hydroiryl, which are attached directly to the metal. Examples or compounds havina the formula time! are trlphenyl tin chloride. triphenyl tin hydroxide, diphenyl tin d1"- chloride. and monophenyl tin trichlorido. All such arcane-metallic compounds will eilectively combine with hydrosen halide in a liquid haloeenated composition when liberated by any cause in such composition.

In the accompanyins drawins. Fig. 1 is a side elevation of a transformer as illustrative of one {arm at electrical device containing a composition embodying my invention; Fla. 2 is a graph showin; the extent at protection afforded paper by tin tetraphenyl in a liquid halogenated composition which is exposed to hydrogen chloride gas: Fig. 3 is a graph showing power factor values over a ranze tainlng a dielectric material embodying my inventlon.

Refer-rim; to Fig. l. the comprises as usual a tank I containing transformer elements comprising essentially a core 1. electrical windings 8. and a quantity or liquid cooling and insulating liquid 1. The tank cover 8 may be tightly sealed. a frangible Window (not shown) beins provided for the cmersency release or excessive gas pressure. All external bushins t or the transformer having no relevance to the present invention has been shown in part broken transformer illustrated of temperatures in capacitors con:

away.

The liquid filling l is liquid haloaenatcd hydrocarbon and may consist cl 0. mixture 0! chlorinated dipheuyl and chlorinated benzene in which the chlorinated diphenyl content may vary widely, say from 1 to 99 per cent. Such a composition swam " may consist of a mixture or trichlorbenaenc and 455 01 October 17. 1983. Various other halogenated compounds may constitute a part or such compositions as well understood. including, ior example. halogenated compounds oi diphenyl oxide. diphenyi tetone, diphenyl methane, dlphenyl ethane. naphthalene and nitro-diphenyl.

The insulation oi the transformer windinzs ordinarily consists oi manila or krait paper about .008 inch in thickness. Cotton and other fibrous insulation may be used. It the cooling and instill-tin: liquid consistina oi chlorinated and compounds is subiected to conditions iavorlna decomposition. hydroren chloride is turned and the pa er insulation in contact with the contaminated liquid becomes quickly deteriorated.

The curve oi Fla. 2 shows the relation oi loss in tensile strensth oi paper in per cent when immersed in a series of chlorinated compositions containina respectively by weiaht from 0.05 to 1.2

'per cent of tin tetraphenyi in solution and exposed to the conditions iavorable to the formation of hydrogen chloride. As indicated by the Iraph. paper immersed in chlorinated compound containing no additive inaredient, thus permittino hydrogen chloride to remain in solution therein, loses about 75 per cent or its tensile strength in one day. On the other hand. paper immersed in the some kind of chlorinated composition containing in solution about .25 per cent of tin tetraphenyl under the same conditions loses only about 5 per cent 01 its tensile strength in the same lenath of time. As indicated by the graph, the loss of tensile strcnsth oi paper under the same conditions resulting in decomposition oi the chlorinated composition is reduced substontiaily to zero it the content of tin tetraphenyl therein is as high as about one per cent. Amounts as low as .05 per cent of a metallic-hydrocarbon present in a chlorinated mi compound produce an advantageous reduction in the harmful chemical eflect oi dissolved hydrogen chloride on paper, cotton or other celiulosic material present therein.

Not only does the presence of an organemetallic compound in a halogenated liquid in the amount by weight or about 0.05 to one per cent reduce the deleterious eilect of such liquid on organic insulation, it also greatly reduces ordi nary rusting of various metals which would occur when metal normally located below the surface oi the liquid chlorinated composition is exposed to air. When a transformer containing such a chicrinaied liquid is drained. for example. for the carrying-out of repairs. exposure to air occur oi surfaces coated with such liquid. Under such conditions rusting occurs which is especially rapid in the presence oi moisture. When, however. the halogenated liquid in contact with surfaces contained an orgauo-metallic compound as herein described. then upon exposure to air rusting is restricted to the amount which normally occurs when clean ierrous metal is exposed to the atmosphere.

A composition embodying my invention advantaseousiy may be used as a liquid dielectric material in capacitors. As described in my prior Patent No. 2,041.594, dated May 19, 1936, chlorinated aryl compounds, and particularly pentachlor dlphenyl, may be used advantageously as 4 capacitor dielectric media. Buch compounds commonly are introduced as an impresnaut tor capacitors in which the armahires are separated by several sheets oi thin paper. It is irequenth' desired to operate such capacitors continuously when the ambient temperature is as high as 90' 6.. or niche!- As shown in Fla. 3 araph ii. the power factor expressed in per cent oi a capacitor impreanated with ordinary pentachior diphenyi tends to tail somewhat as the ambient temperature is increased irom about 25' C. to about 00' O, The power factor rises with iurther increase in temperature above 0. when the some type of capacitor is impregnated with peutachlor diphenyi havin: associated therewith about onequarter per cent at tin tetraphenyl. as shown by sraph i2, lower power factor values accompany operation over an elevated reuse oi we tests have shown that capacitors containin; an crgano-metallic c mpound such. for example. as tin tetraphenyl. have a ionaer useiul liie and a Ireater dielectric stability than exactly similar capacitors unprovided with such compound. Capacltors containing oraanc-metallic compound do not show the slow rise oi power factor with time when operated in a high amhlent temperature which is characteristic of capacitors impregnated with chlorinated dielectrio materials which are unassoclated with an organo-metallic compound.

The advantages accruina irom my invention are obtained in electric switches. When chlorinated diphenyl or other suitable halogenated aryl compounds are employed in electric switches. the unavoidable arcing which accompanies makeond-break or the switch terminals results in some decomposition. The hydrogen halide thus formed is rendered innocuous by the presence oi an organo-metailic compound. Switches so provided are practically tree from the rusting and corrosion which ordinarily accompanies the use of switches ililed with halogenated hydrocarbons.-

Reierence has been made herein to tin tetraphenyl and other examples of my invention. Other organo-metallic compounds which may be associated with halogenated hydrocarbons for the purposes oi my invention, include among the tin compounds. the tetramethyi and the tetracthyl compounds. Mercury compounds, such as the methyl and the ethyl, constitute other examples. Lead compounds, such as lead tetramethyl or lead tetraetbyl. may be used as inhibitors. In aeneral. tin tetraphenyl dibutyl dlphenyi tin and lead tetraphcnyi are preferred examples of inhibitors embodying my invention.

Although the advantages of my invention have been stated with reference to holosenated aryl compounds. it should not be considered as being limited solely to such compounds. Balogenated alkyl compounds may be stabilized by the addition or crane-metallic compounds.

What I claim as new and desire to secure by Letters Patent oi the United States is:

l. A liquid dielectric and insulating composition consisting essentially oi haloaenated sryl hydrocarbon and containina in solution by weight about 0.05 to l per cent of an oraano-metallic compound chosen (ruin the group consisting oi compounds havina the formulae MR: and MRY in which M is a metal chosen from the group consistin: oi tin. lead and mercury. R is an arcmatic radical. a: is an integer in the range cl 2 to 4 and Y is a halogen.

' 2. A normally liquid dielectric and insulating composition consisting essentially of halogenated aryl hydrocarbon and containing in solution by weight about one-fourth to one per cent of organo-metalllc compound having the iormula HR: in which M is a metal chosen from the group consisting of tin, lead. and mercury; R is an organic radical chosen from the group consisting oi aliphatic and aromatic radicals; combinations such radicals and radical containing substituents; and a: is an integer in the range of 2 to 4.

3. A normally liquid dielectric and insulating composition consisting essentially of halogenated and hydrocarbon and containing in solution by weight about one-fourth to one per cent of organo-metallic compound having the formula MR=Y in which M is a metal chosen from the group consisting of tin, lead, and mercury; R is a radical chosen from the group consisting of aliphatic and aromatic radicals, combinations of such radicals, and such radical containing substituents, a: is an integer in the range of 2 to 4, and Y is an inorganic substituent chosen irom the group consisting of halogen and hydroxyl attached directly to the metal.

4. The method of rendering innocuous hydrogen halide formed in liquid halogenated aryl hydrocarbon when subjected to decomposing influencc which consists in causing such hydrogen to combine chemically with an organo-metallic comchosen from the group consisting oi compounds having the formulae MR: and MRrY in which M is a metal chosen from the group consisting oi tin, lead and mercury, R is an aromatic radical. :0 is an integer in the range of 2 to 4, and Y is a halogen.

5. An electrical device comprising cooperating electric elements and a liquid chlorinated aryl hydrocarbon cooling and insulating medium therefor, said medium containing in solution by weight about one-iourth to one per cent of orchosen from and mercury.

the group consisting of tin, lead R is an aromatic radical and :r is

an integer in the range of 2 to 4.

6. A liquid composition suitable for dielectric purposes consisting of chlorinated aryl hydrocarbon and in admixture therewith about .05 to 1.2 per cent '1. A capaci of tin tetraphenyl.

tor dielectric material consisting of pentachlor diphenyl having associated therewith about one-quarter per cent of tin tetraphenyl.

8. Dielectric and insulating liquid compositions consisting of chlorinated aryl hydrocarbon and about .05. to .25 per cent of tin tetraphenyl.

9. An electrical device provided with a dielectric and insulating element consisting of a halogenated aryl hydrocarbon containing in solution therewith about .05 to 1.2 per cent of tin tetraphen l 10. A liquid dielectric and insulating composition including chlorinated diphenyl as an ingredient and containing in solution by weight about 0.05 to 1 per cent pound of a sisting of tin, attached directly to a matlc radical.

oi an organo-metallic commetal selected from the group conlead, and mercury, the metal being carbon atom or an arc- FRANK M. CLARK REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number McLean Oct. 21, 1941 

